3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 145 · 40 questions

How to do it in your head (Hundreds first): Keep the first number as it is and split the second into hundreds, tens and ones. Add (or take away) the hundreds first, then the tens. Finish with the ones — bridge through a ten if you need to.

1. 1.785 − 507 =
2. 2.621 + 329 =
3. 3.439 − 122 =
4. 4.468 + 264 =
5. 5.671 − 141 =
6. 6.465 − 118 =
7. 7.893 − 603 =
8. 8.987 − 415 =
9. 9.710 − 235 =
10. 10.745 + 606 =
11. 11.628 − 206 =
12. 12.251 + 365 =
13. 13.553 − 229 =
14. 14.506 + 151 =
15. 15.439 − 188 =
16. 16.400 + 151 =
17. 17.780 − 555 =
18. 18.645 + 625 =
19. 19.748 − 592 =
20. 20.548 + 482 =
21. 21.859 − 432 =
22. 22.683 − 561 =
23. 23.473 + 578 =
24. 24.919 − 143 =
25. 25.716 − 214 =
26. 26.682 + 281 =
27. 27.287 + 583 =
28. 28.239 + 345 =
29. 29.590 − 214 =
30. 30.594 + 152 =
31. 31.217 + 374 =
32. 32.789 − 579 =
33. 33.893 − 759 =
34. 34.221 + 397 =
35. 35.674 + 356 =
36. 36.447 + 265 =
37. 37.698 − 222 =
38. 38.721 − 184 =
39. 39.694 + 449 =
40. 40.353 + 173 =

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths